form RenderControl doesn't work in win app

[Ken Boone via .NET 247]

I am trying to render the html for a page with a form on it. When I try it in an ASP.NET app, it works fine. When I use the same code in a Win App, it doesn't. Here's how to replicate what I've done.

----------------
The ASP.NET app:
----------------
1. Make a new web project.
2. Add a Button and a TextBox to default WebForm1.aspx.
3. Make TextBox.TextMode = MultiLine.
4. In Button1_Click, add this code:

System.IO.StringWriter sw = new System.IO.StringWriter();
System.Web.UI.HtmlTextWriter htw = new System.Web.UI.HtmlTextWriter(sw);

System.Web.UI.Page p = new System.Web.UI.Page();
System.Web.UI.HtmlControls.HtmlForm hf = new System.Web.UI.HtmlControls.HtmlForm();
p.Controls.Add(hf);
p.RenderControl(htw);

TextBox1.Text = sw.ToString();

5. Run the project and click the button. You'll get the following output in TextBox1:

<form name="_ctl0" method="post" action="WebForm1.aspx" id="_ctl0">
<input type="hidden" name="__VIEWSTATE" value="" /></form>


----------------
The WinForm app:
----------------

1. Now make a WinForm project.
2. Add a Button and a TextBox to the default Form1.cs.
3. Rename the TextBox to TextBox1 and make TextBox1.MultiLine = True.
4. In button1_Click, add the same code as above.
5. Add a reference to System.Web.
6. Run the project and click the button. You'll get an error on the line after the RenderControl line:

An unhandled exception of type 'System.NullReferenceException' occurred in system.web.dll

Additional information: Object reference not set to an instance of an object.


Any ideas?

 

[Norman Yuan]

Web app and Win app are different things, you cannot simply use the same
code run in both apps without knowing how they run so much differently.

I am trying to render the html for a page with a form on it. When I try

it in an ASP.NET app, it works fine. When I use the same code in a Win App,
it doesn't. Here's how to replicate what I've done.